The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Near field communication (NFC), such as Bluetooth, often uses phase-shift keying (PSK) to communicate symbols. A PSK symbol's phase correlates to a particular symbol (e.g, in D8PSK, 45 degrees corresponds to 110, 90 degrees corresponds to 010, and so on). Constellation diagrams are used to represent PSK symbols in the I-Q plane based on the symbols' real and imaginary components. In the constellation diagram, the real component is graphed along the I axis and the imaginary component is graphed along the Q axis. Before a signal corresponding to a succession of PSK symbols is transmitted, the signal is filtered to so that the transmitted signal transitions smoothly from one symbol to the next.